Hydrochlorofluorocarbons are widely used as solvents, cleaning agents, blowing agents, and refrigerants. It is desirable that the hydrochlorofluorocarbon which is selected for such uses possess stability and freedom from toxic impurities. Olefinic impurities which are often present as impurities in the hydrochlorofluorocarbon may be toxic and/or unstable.
Hydrochlorofluorocarbons have been produced by methods such as the chlorination of fluorohydrocarbons, fluorination of hydrochlorocarbons, exchange reactions between hydrogen fluoride and hydrochlorocarbons, or the addition of chlorine, fluorine, hydrogen chloride, or hydrogen fluoride to halogenated olefins.
In several of these known methods, the resultant hydrochlorofluorocarbon typically contains at least traces of olefinic impurities even after fractional distillation.
Known methods for purifying hydrofluorocarbons containing olefinic impurities include reaction with aqueous potassium permanganate, amines, oxygen, sulfuric acid, or hydrogen fluoride. Each of these methods has significant disadvantages for hydrofluorocarbon purification such as requiring extensive operations, producing undesirable residues, and/or destroying undesirable amounts of the compound to be purified. These methods are at least as disadvantageous for purifying hydrochlorofluorocarbons because hydrochlorofluorocarbons are generally more subject to undesirable side reactions.